69 lines
965 B
C++
69 lines
965 B
C++
#include <iostream>
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#include <stdio.h>
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#include <algorithm>
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#include <string.h>
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using namespace std;
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int n, w;
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int data[1000];
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int interval [1000];
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void solve()
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{
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int k = 0;
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double sum = 0.01;
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sort(data + 1, data + n + 1);
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while(!(data[n] >= k*w && data[n] <= (k+1)*w-1))
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{
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k++;
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}
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memset(interval, 0, sizeof(interval));
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for(int i = 1; i <= n; i++)
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{
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int kk = 0;
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while(kk <= k)
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{
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if(data[i] >= kk*w && data[i] <= (kk+1)*w-1)
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{
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interval[kk] ++;
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break;
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}
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else
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{
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kk++;
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}
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}
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}
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int max = 0;
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for(int i = 0; i <= k; i++)
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{
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if(max < interval[i])
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{
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max = interval[i];
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}
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}
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for(int i = 0; i <= k; i++)
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{
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sum += ((double)interval[i]) / ((double)max) * (k-i) / k;
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}
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printf("%.6lf\n", sum);
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}
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int main()
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{
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while(1)
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{
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scanf("%d%d", &n, &w);
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if(n == 0 && w == 0)
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{
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break;
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}
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else
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{
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for(int i = 1; i <= n; i++)
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{
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scanf("%d", &data[i]);
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}
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}
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solve();
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}
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return 0;
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}
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